Hello all:

After playing around with our other 87 300D, I found out that indeed the ALDA holds pressure, though not vacuum. Beats me why. Anyway, it still seems to lack some power. So far I have:

Replaced ALL underhood vacuum lines and fittings
Replaced air filter, fuel filters and did diesel purge
Boost is 10 psi max and turbo spools up well
Cleaned ALDA fitting and manifold connector

I connected the line from the manifold directly to the ALDA, and there was no improvement. What frustrated me even MORE is that I disconnected the boost sensing line from the manifold of my other 300D (the fast one) and it drove JUST like this one - meaning that it feels like a non-turbo 603. It seems that the boost is getting sent to the ALDA but there isn't any extra fuel delivery going on here. Looks like I'll have to pull the manifold (not too fun) and dissect the ALDA. Thanks in advance for any help or suggestions.